Grant Number:	1R03CA289843-01A1 Interpret this number
Primary Investigator:	Marcus, Michele
Organization:	Emory University
Project Title:	Cancer Outcomes Among Michigan Residents Exposed to Polybrominated Biphenyls
Fiscal Year:	2025

PROJECT SUMMARY In 1973, an industrial accident resulted in the shipping of a brominated flame-retardant chemical instead of a nutritional supplement to farms across Michigan. The mix-up led to the widespread contamination of the Michigan food supply, exposing an estimated nine million Michiganders to polybrominated biphenyl (PBB). In response to the disaster, the Michigan Department of Health and Human Services (MDHHS) created the Michigan Long-term PBB Registry. The study was created to examine the adverse health effects associated with exposure to PBB. One of the primary concerns of the exposed community was whether exposure to PBB would increase their risk of cancer. Fifty years after the PBB disaster, the affected community still does not have an acceptable answer to this question; although, preliminary evidence points to an increased risk of several cancer types. Dr. Michele Marcus and her team at Emory University have formed a strong academic- community partnership which now seeks to provide the affected community with some answers regarding their cancer risk. The Michigan PBB Registry includes over 7,500 ever-active participants and now includes children and grandchildren of those who ate the contaminated food. The PBB disaster provides a unique opportunity for scientific inquiry, while also addressing a pressing community concern. Since PBB had a defined exposure window, there is a possibility to study the harmful effects of an endocrine disrupting chemical during specific lifestages (i.e. adulthood, childhood, in utero). Additionally, while PBB is no longer produced in the United States (US), it has a similar chemical structure to other commonly used brominated flame retardants and shares many concerning properties with other contemporary chemicals (i.e. lipophilic, long half-life, resistant to environmental degradation). Our study seeks to understand the potential association between serum PBB levels and cancer incidence and mortality. We have linked the Michigan PBB Registry to the National Death Index to obtain mortality data and are in the process of linking to two state cancer registries to obtain cancer incidence and mortality data. We will utilize standardized incidence and mortality ratios to first understand if there is a higher burden of cancer in the Michigan PBB Registry compared to the general US population. Next, we will utilize longitudinal and survival models to examine the association between serum PBB levels (measured at several timepoints) and cancer incidence/mortality and time to these events, respectively. We will also examine these models stratified by lifestage at exposure. Our proposal also includes a review of our biorepository, that includes over 35,000 additional stored samples, to identify samples taken before and after cancer diagnoses to set up future nested case-control studies to examine underlying biological mechanisms. It is our hope that this study contributes not only to our understanding of the role of endocrine disrupting chemicals in cancer but provides much needed information to the affected community which can utilize this information to make informed healthcare decisions with their providers about cancer screening.





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